Production of esters



April 13 1926.

D. AL L EGG Er AL PRODUCTION OF ESTERS Filfgd June 16, 1925 Patented pr. k13, 1926.

UNITED STATES 1,580,143 PATENT ,ol-FI-CE.`

DAVID A. LEGG AND CHARLES BOGIN, OF TERRE HAUTE, INDIANA, AASSIGNORS T COMMERCIAL SOLVENTS CORPORATION, 0F TERRE HAUTE, INDIANA, A CORPORA- 'rIoN or MARYLAND.

PRODUCTION or Esrnnsf Application mea June 16, 1923. serial No. 645,756.

To all whom z't may concern: Y

Be it known that we, DAVID A. LEGG, a subject of the King of Great Britain and Ireland, and CHARLES Boom, a citizen of the United States, both residents of Terre Haute, in the county of Vigo and State of Indiana, have invented certain new and use-- ful Improvements in the Production of Esters, of which the following is a specification, reference being made to the accompanying drawings, forming a part thereof.

Our invention relates particularly to the production of esters during the catalytic deydrogenation of aliphatic aldehyde-forming alcohols in the vapor phase, and the objects of our invention are, among other things to provide a novel simplified method by which such esters may be readily formed from the corresponding alcohol by the reaction occurring in the vapor phase in the presence of particular forms of catalysts. It is well known that the catalytic interaction of aldehydes to form esters has been applied on a laboratory scale in the liquid phase, as set forth by Tischtchenko, BeiL stein, Handbuch der organischen Chemie, 4th Edition, vol. 2, page 291. This general equation may be expressed as follows wherein R represents a hydrocarbon radicle. We have discovered a new and useful method of utilizing this reaction occurring in the vapor phase in the presence of certain hereinafter described catalysts resulting in far better yields than have hitherto been ob-v tained in industrial scale operations.

While our invention is capable of embodiment in many different forms, for the purpose of illustration we shall describe only `one form of our methodyand while. said method is capable of being carried out with many different types of apparatus, yet for` in the production of normal butyl aldehyde and normal butyl butyrate.

In the drawing we have shown only asingle unit of the apparatus; however two or more units connected in series may be used to better advantage.

Referring to the drawing in order to understand how our improved method may be carried out, a quantity of alcohol, for kexample, normal butyl alcohol is poured in the reservoir 1 Seton the shelf 2 from which 1t iows by gravity through the pipe 3 at a definite rate through sight feed-gauge glasses 4 and then by pipe 5 into the steam preheater 6 heated by live steam from the inlet pipe 7. Within the preheater 6 is the iiash boiler Sipreferably formed in a copper coil with the copper coil pipe 9 leading from the boiler 8 to the conduit 10. The condensed steam from thepre-heater 6 is discharged through the outlet pipe 1'1. During the course of this run the butyl alcohol is vaporized and then preheated to 125 C. or even higher after which it is passed through conduit 10 into the catalyzer.

The catalyzing apparatus comprises the outer heat batiie cylinder 12 suitably set in' brickwork 13 having lateral spaced-apart baiiies 14. Set within the cylinder 12 is the container -15 supported on the annular bracket 16 by the circular bead 17 extending lfrom the open rim of the container 15. Projecting from the sides of the container 15 are lateral spaced-apart baies 18 dovetailed between the battles 14. The bottom of the container 15 has a series of downwardly-extending ribs 19 over the gas-jets-2O formed in the top yof the burner 21 connected by the pipe 22 with any suitable source of gas supply (not shown).

Supported concentrically' within the container 15 is the outer catalyst cylinder 23 having the inlet cor'24 connected at its upper end to the conduit 10; the core 24 opens at its lower end into the vapor distributing chamber 25 formed in the bottom of the cylinder 23. Concentrically disposed Within the cylinder 23 is the inner catalyst area 27 filled preferably with a suitably pre ared catalyst such as is described in United tates Legg Patent No. 1,401,117 dated December 20, 1921. The lower end of the cylinder 26 rests on the plate 28 the marginal periphery of which is perforated to al ow the vapors to pass from the chamber 25 into the catal st area 27. The upper ortion of the cylin-V der 26 is formed with the chamber 29 having holes ,in its sidewalls through which the reaction products pass as indicated by arrows) through the out et pipe to the vcondenser 31 lhay/ing the usualmlet and outlet pipes 32 and 33 res ectively for cooling Water which circulates a out the coil 34 Within the condenser 31. The condensed products pass from the coil 34 through the pipe 35 and are caught in any suitable receiver 36 set on standards 37, The container 15 holds any suitable heat exchanging medium- 38, in the present instance, a bath of molten solder is preferably used.

As an example of the use of our improved method in carrying out same in industrial ractice, 6600 pounds of normalbutyl alco- =ol were placed in reservoir 1 and then vaporized and heated to about'125 C. in the preheater 6 from which the vapors passed through the inlet conduit 10 and inner` core 24 to the vapor distributing chamber 25 and thence upwardly as indicated by. the arrows through the perforations in the plate 28 iritothe catalyst area 27 which was filled with a fused cupric oxide catalyst formed as a fused, spongymass, and crushed into lumps of suitable size, say of one inch cubes, such asis described in the aforesaid United States Legg Patent No. 1,401,117. Here the alcohol vapors were decomposed with a resultant mixture consistinglargely of butyric aldehyde, butyl alcohol,y butvl butyrate and hydrogen. Such reaction products were then passed through the outlet pipe 30 to another similar unit and then to the condenser 31 in vthe usual manner to separate the hydrogen. During this decomposing operation the molten solder 38 in the container 15 surrounding the catalyst and vapors was maintained at a temperature ranging from 280 C. to. 300 C. by means of the gas jets 20. Y

rlhe crude condensed product caught in the receiver 36 consisting of butyric aldehyde, butyl alcohol, butyl butyrate and butylidene dibutyl ether was then distilled to separate the aldehyde therefrom and the residue was then distilled with dilute ,sulphuric acid (1 to 2%) to decompose Ithe utylidene dibutyl ether.

We found the distillate from this mixture consisted ot three main fractions, viz :w

A. Butyraldehyde.

B. Butyl aldehyde and butyl alcohol and water.

C. Butyl alcohol and butyl butyrate and water.

rllhe C fraction was then run into a separating tank and the lower layer ot water removed the residue was then distilled to remove as much butyl alcohol as possible, and the inal residue consisting of 1050 pounds was found to contain 52% butyl utyrate. rllhis butyl butyrate can be readi y separated from butyl alcohol by distillation vreservoir 1.

It' will be understood that many modificatlons may be made in the form andarrangement of the apparatus used for carrying out our improved method for the production of esters without changing the essential princi- -ples of the process or the operation in such apparatus.

We claim as .our invention:

v1. The method of producing esters which comprises passing normal butyl alcohol in the vapor phase over a dehydrogenating copper-containing catalyst at a temperature between 260 and 320l C., then separating part of the aldehyde produced, and finally fractionating the residue to recover the esters formed therein.

2. rlhe method of producing esters which comprises preheating vaporized normal butyl alcohol to a temperature of about 125 C., then passing same over a dehydrogenating copper-containing catalyst at a temperature between 260 and 320 C., then separating part of the aldehyde roduced, and finally fractionating the resi ue to recover theesters formed therein. 4

3. 'lfhe method for producing butyl butyrate which comprises passing normal butyl alcohol in the vapor phase over a copper catalyst at atemperature between 260 and 320 C., then condensing the reaction mixture to remove hydrogen, then distilling the resultant product to Separate art of the aldehyde produced, and final y separating from the distillate the water and butyl alcohol with the recovery of butyl butyrate therefrom.

d. 'llhe method for producing butyl butyrate which comprises preheating vaporized normal butyl alcohol to a temperature of about 125 C., then passing it over a dehydrogenating catalyst comprising fused and crushed cupric oxide at a temperature between 260 and 320 C., then condensing the reaction mixture to remove hydrogen, then distilling the resultant product to separate part of the aldehyde produced, and linally separating the butyl butyrate formed from the butyl alcohol and water.

5. ln the method for producing esters from normal butyl alcohol the steps which consist in subjecting the alcohol in a vapor phase to the action of a dehydrogenatlng copper-containing catalyst at a temperature between 260 and 320 C. and thereafter. con- (lensing, distillin -the resultant roduct to separate part of t e aldehyde produced, and inally 'separating and recovering esters formed in the residue.

6. In the method for producing 'esters from norrnal butyl alcohol the steps which consist in subjecting the alcohol in a va or phase to the laction of` a dehydrogenatmg ester-producing catalyst comprising fused and crushed cupric oxide at a tem eraturcbut 1 10 formed in the residue.

7. In the method for producin butyrate from` normal butyl alco o1 t e' 'steps which consist lin suhjecting thevaporreheated to a. temperature of ized alcohol to the action .of ardehydroabout 125 `genating catalyst comprising vfused 'endev crushed cupric oxide at a temperature between 26 and 320 C. and thereafter' condensing, distilling the resultant roduct to separate part of the aldehyde pro uced, 'and nally separating and recovering esters formed inthe residue. Y

n DAVID A. LEGG.

CHAS. -BOGIN. 

